Some surprising science fact that many people don't know, an animal egg (chicken, birds, etc) is a single cell, so there's a huge variability in the weight of a cell.

There are some very large single celled organisms that aren’t eggs. E.g.:

https://en.wikipedia.org/wiki/Valonia_ventricosa

https://en.wikipedia.org/wiki/Foraminifera

Even some bacteria can grow to visible size:

https://en.wikipedia.org/wiki/Thiomargarita_magnifica

There are some other examples here:

https://en.wikipedia.org/wiki/Largest_organisms

I found this claim unbelievable, but it is mostly true. It isn't quite the whole egg, it is just the yolk. But that's still a very large cell!

http://cnet.com/home/kitchen-and-household/appliance-science... verifies this.